Advanced molecular modelling techniques to determine structures and reaction mechanisms of catalytic processes at the atomic level

This thesis focuses upon an examination of small nanoparticles of particular relevance to catalytic processes. The first chapter provides an introduction to the topics discussed throughout this work. The second chapter contains a discussion of the theoretical underpinnings of the computational chemistry techniques that have been applied throughout the work. An examination of the modelling of palladium nanoparticle seed solutions using atom-centred density functional theory and time-dependent density functional theory is presented within the third chapter. The fourth chapter introduces a case study upon the electronic properties of Au19 which utilises various descriptor functions to examine and characterise the electronic structure of Au19 and proposes a machinelearning derived method for examining and approximating tensor properties, with a particular application demonstrated in the calculation of the elasticity of Au19. The work in the fifth chapter introduces a range of novel methodologies based upon a unique approach to continuous symmetry measurement and a software code developed to implement these measurement techniques. This symmetry measurement is then applied to the characterisation of nanoparticle structures, as well as a diverse range of molecular species. Chapter six analyses the work as a whole and draws conclusions based upon the results of each section